Fossil Hunting at Como Bluff, Wyoming
ALLOWED
No permit required
Key Conditions
- Invertebrate and plant fossils: casual collection allowed up to 25 lbs/day on BLM land under PRPA 2009
- Vertebrate fossils (dinosaur bones, teeth, tracks, and any fish or reptile material): prohibited from casual collection — all vertebrate material must be left in place
- No motorized excavation tools; hand tools only for surface and near-surface collection
- Any vertebrate fossil discovery must be reported to the BLM Rawlins Field Office at (307) 328-4200
- No permit required for invertebrate/plant casual collection; research permit required for any vertebrate collection (not available to public recreationists)
The Bone Wars between Othniel Charles Marsh and Edward Drinker Cope put Como Bluff on the map of American science in the 1870s. Marsh's Yale college scouts discovered dinosaur bones eroding from the Morrison Formation at Como Station in 1877; within months both Marsh and Cope had crews excavating competing quarries along the bluff. The specimens pulled from Quarries 1 through 13 here — including type specimens for Diplodocus longus and Camarasaurus supremus — now anchor collections at the Smithsonian, Yale Peabody, Carnegie Museum, and the American Museum of Natural History.
The site is publicly accessible BLM land today. What has not changed is the formation itself: Late Jurassic Morrison sandstone and mudstone, the same rock unit that produced those landmark discoveries, still erodes naturally across the bluff face. What has changed is the legal framework — PRPA 2009 prohibits any casual collection of vertebrate paleontological resources from federal land. The Morrison at Como Bluff is almost entirely vertebrate-bearing. Visitors who come expecting to pocket a dinosaur tooth will leave empty-handed and potentially facing a federal citation.
Dinosaur fossils here are federally prohibited from casual collection — this includes surface finds
The Paleontological Resources Preservation Act (PRPA 2009, 16 U.S.C. § 470aaa) prohibits casual collection of vertebrate fossils on all BLM land. At Como Bluff, vertebrate fossil material — bone fragments, teeth, tracks — weathers continuously from the Morrison Formation. Picking up a bone chip and putting it in your pocket is a federal violation, regardless of how small the fragment is or whether it looked like rock at first glance. Penalties for knowing violations include criminal fines up to $100,000 and up to one year of imprisonment. The rule covers all vertebrate fossils: dinosaur, fish, marine reptile, and mammal. If you find bone material, photograph it in place, record GPS coordinates, and contact the BLM Rawlins Field Office at (307) 328-4200.
PRPA 2009 — What You Can and Cannot Collect Here
The Paleontological Resources Preservation Act of 2009 establishes two collection categories on all federal land:
Casual collection (no permit required): Surface collection of invertebrate and plant fossils, up to 25 lbs/day on BLM land. At Como Bluff this means: bivalves and brachiopods from Sundance Formation limestone, petrified wood from Morrison mudstones, invertebrate trace fossils.
Restricted collection (permit required): All vertebrate fossils — bones, teeth, tracks, eggs — regardless of size or apparent condition. Research permits for vertebrate fossils are issued to qualified paleontologists through academic institutions. No casual or hobbyist collection is permitted for any vertebrate material under any circumstances.
The practical implication at Como Bluff: the Morrison Formation is overwhelmingly vertebrate-bearing. The more accessible casual-collection targets are in the underlying Sundance Formation marine layers.
Como Bluff at a Glance
Allowed (25 lb/day)
Invertebrate collecting
Prohibited — PRPA
Vertebrate (dinosaur) collecting
No (invertebrates/plants)
Permit required?
~148–160 Ma (Jurassic)
Formation age
Medicine Bow (~6 mi)
Nearest services
BLM Rawlins FO
Managing agency
Getting to Como Bluff
Access road and shoulder conditions verified July 2026. Check BLM Rawlins FO (307) 328-4200 for current road conditions in wet periods.
Como Bluff vs. Other Fossil Hunting Sites
| Site | Formation | Casual collection? | What's collectable | Notes |
|---|---|---|---|---|
| Como Bluff BLM (WY) | Morrison + Sundance (Jurassic) | Invertebrates/plants only | Sundance marine invertebrates, petrified wood | Famous dinosaur site; vertebrates prohibited PRPA |
| Hell Creek BLM (MT) | Hell Creek (Cretaceous) | Invertebrates/plants only | Bearpaw Shale ammonites, petrified wood | Same PRPA vertebrate prohibition; Cretaceous marine |
| San Rafael Swell BLM (UT) | Various (Triassic-Cretaceous) | Invertebrates/plants only | Marine invertebrates, petrified wood | Accessible; extensive exposures; same PRPA rules |
| Grand Staircase-Escalante BLM (UT) | Cretaceous | Common invertebrates only (25 lb/day) | Marine bivalves, ammonite fragments | Excellent exposure; more remote sections require planning |
| Dinosaur NM (UT/CO) | Morrison (Jurassic) | Prohibited (NPS) | Observation only | Carnegie Quarry wall shows 1,500+ bones in situ — best place to see Morrison vertebrates without collecting |
Collection rules verified from BLM and NPS managing agency sources, July 2026. PRPA vertebrate prohibition applies at all federal land fossil sites regardless of formation.
Pre-Visit Checklist — Como Bluff
- Download offline BLM surface management map with land-status layer — private parcels exist within the area
- Review PRPA vertebrate vs. invertebrate distinction before arrival — know what you can and cannot collect before you are in the field
- Carry GPS or location-tracking app — coordinates of any vertebrate find must be recorded for reporting to BLM
- Pack at minimum 1 gallon of water per person — no water source within 6 miles
- Check weather forecast: afternoon thunderstorm risk is high July–August on exposed high-plains terrain
- Note BLM Rawlins Field Office number: (307) 328-4200 — required contact for vertebrate fossil reporting
Permits & Licenses
| Permit | Required? | Notes |
|---|---|---|
| Casual fossil collection (invertebrates and plants) | No | No permit required for casual collection of invertebrate and plant fossils on BLM land. Subject to the 25 lb/day limit under 43 CFR § 3622.2. |
| Vertebrate fossil collection | Yes | A paleontological resource permit is required for any vertebrate fossil collection on federal land under PRPA 2009. These permits are issued to qualified researchers through academic institutions; they are not available to public recreationists. In practice: do not collect vertebrate material at Como Bluff under any circumstances. |
Time & Seasonal Restrictions
- Vertebrate fossils (dinosaur bones, teeth, tracks; fish remains; marine reptile fragments): prohibited from casual collection under PRPA 2009 — all must remain in place and be reported if discovered
- 25 lb/day maximum for invertebrate and plant fossils on BLM land under 43 CFR § 3622.2
- Motorized excavation prohibited; hand tools only for near-surface collection
- Do not disturb or undercut the formation face — rockfall risk and irreversible damage to fossil-bearing layers
- Private land parcels are interspersed with BLM land in the Como Bluff area — verify land status before collecting in any particular zone (BLM Rawlins FO maintains land status maps)
Equipment Notes
- BLM surface management map or downloaded offline parcel map — private land parcels exist within the area; knowing boundaries before collecting is essential
- Hand tools only: rock hammer, cold chisel, dental pick, stiff brush — motorized excavation is prohibited
- GPS coordinates of any significant find — PRPA requires reporting significant or vertebrate finds to the BLM; precise location data is required
- Water (at least 1 gallon/person in summer) — no facilities exist at Como Bluff; Medicine Bow is the nearest supply town (6 miles east)
- High-clearance vehicle recommended for rough BLM access roads off US-30/287
What People Find Here
- Permineralized bivalves (Gryphaea arcuata) from the Sundance Formation marine layers — robust curved shells that weather free from the limestone; the most accessible casual-collection find at this site
- Brachiopods from the Sundance Formation marine limestone — less common than bivalves but distinguishable by bilateral symmetry and ribbed texture
- Petrified wood fragments from Morrison Formation mudstone and sandstone beds — silicified logs and branches are common surface finds
- Marine invertebrate trace fossils (burrows, feeding traces) in Sundance limestone beds — technically collectable as invertebrate fossils
- NOTE: Dinosaur bone fragments in tan and red Morrison sandstone are common surface finds throughout the site — all must be left in place and reported if identifiable as vertebrate material; misidentifying bone as petrified wood is the most common violation at this site type
Penalties for Violations
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| Violation | Statute | Penalty |
|---|---|---|
| Casual collection of vertebrate fossils without a permit | PRPA 2009, 16 U.S.C. § 470aaa-5 | Civil penalty up to $500 for first offense; criminal penalty up to $100,000 fine and 1 year imprisonment for knowing violations; fossils and equipment confiscated |
| Exceeding 25 lb/day personal-use limit for invertebrate/plant fossils | 43 CFR § 3622.2 | Civil penalties up to $500 per day; enhanced penalties for commercial-scale violations |
| Using motorized excavation equipment | BLM land use conditions / PRPA 2009 site protection | Civil penalties; potential criminal charges if significant paleontological resource is damaged |
| Failure to report a significant vertebrate fossil find | PRPA 2009, 16 U.S.C. § 470aaa-3 | Civil penalties; PRPA requires prompt reporting of significant discoveries on all federal land |
Etiquette & Leave No Trace
- Photograph any dinosaur bone fragment before leaving it in place — BLM rangers and researchers want documented GPS locations of in-situ vertebrate finds; your photo and coordinates may contribute to a future research study
- Do not undercut the formation face or roll loose rock off ledges — this permanently destroys the stratigraphic context of fossils still embedded in the rock
- Pack out all trash — there are no facilities at Como Bluff, and the open high-plains site is used year-round by both hobbyists and researchers
- If you encounter another party actively digging vertebrate material, note the location and report it to the BLM Rawlins FO — unauthorized vertebrate collection is a federal crime
- Tell someone your planned access route; the site is remote and cell service is limited in the Como Bluff drainage
Nearby Alternatives
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| Site | Distance | Notes |
|---|---|---|
| Grand Staircase-Escalante NM (BLM) | 400 mi | Utah BLM; invertebrate casual collection allowed; different formation (Cretaceous marine); high-scenic backdrop |
| Hell Creek BLM (Montana) | 600 mi | Cretaceous; ammonites and Bearpaw Shale invertebrates allowed for casual collection; vertebrates prohibited under same PRPA framework |
| Dinosaur National Monument (UT/CO) | 350 mi | NPS; all collecting prohibited — but the Carnegie Quarry wall contains 1,500 exposed bones in situ; best site in the US for observing Morrison Formation dinosaurs without collecting |
Frequently Asked Questions
Can I collect dinosaur fossils at Como Bluff?
No. Dinosaur fossils are vertebrate paleontological resources and are prohibited from casual collection on all federal land under PRPA 2009 (16 U.S.C. § 470aaa). The Morrison Formation at Como Bluff is famous for producing Diplodocus, Camarasaurus, Stegosaurus, and Allosaurus specimens — all of which are off-limits. Only invertebrate and plant fossils from the site can be casually collected, subject to the 25 lb/day limit.
What is the difference between the Sundance Formation and the Morrison Formation here, and why does it matter for collecting?
The Sundance Formation sits below the Morrison here and represents a Middle Jurassic shallow sea that covered Wyoming roughly 155-160 million years ago. It contains marine invertebrates (bivalves, brachiopods, ammonites, trace fossils) — the kind of material that can be casually collected. The overlying Morrison Formation (~148-155 Ma) is where the famous dinosaurs come from, and most of its fossiliferous material is vertebrate. Surface-collected petrified wood from Morrison mudstones is also collectable. Understanding which layer you are on tells you immediately whether what you find is potentially collectable or must be left in place.
Is the Bone Cabin still standing and can I visit it?
The original Bone Cabin Quarry is located approximately 5 miles east of Como Bluff proper on US-30, near the hamlet of Medicine Bow. The cabin built from dinosaur bones in 1897 by Thomas Boylan was a roadside attraction for decades, but the structure has deteriorated significantly. The Wyoming State Historic Preservation Office (SHPO) lists the site; access conditions vary. The cabin location is distinct from the numbered Como Quarries on the bluff itself.
How do I know if a bone fragment I find is vertebrate fossil or just rock?
Fresh dinosaur bone from the Morrison Formation is typically a brown, tan, or orange color, with a distinctive spongy interior texture visible at any break. Petrified wood shows growth rings or bark texture. Plain sandstone concretions (very common in Morrison mudstones) are uniform grained without internal structure. If you are uncertain, the rule is simple: leave it in place, photograph it, record the GPS coordinates, and report it to the BLM Rawlins Field Office at (307) 328-4200. Misidentifying vertebrate bone as petrified wood is not a defense under PRPA.
How do I report a significant vertebrate fossil find at Como Bluff?
Contact the BLM Rawlins Field Office at (307) 328-4200. Provide the GPS coordinates of the find, a photograph if possible, and your contact information. Do not move, excavate, or remove the specimen. PRPA 2009 requires prompt reporting of vertebrate or potentially significant paleontological resources discovered on federal land; the BLM will determine whether a research team needs to assess the site.
Disclaimer
Information is provided for general guidance only. Regulations change frequently. Always verify current rules with the official jurisdiction before relying on this information for legal decisions. Permitted Pursuits is not a substitute for official agency guidance. Report an error.
Sources
- BLM Paleontological Resources — PRPA Information(accessed 2026-07-01)
- BLM Rawlins Field Office(accessed 2026-07-01)
- Paleontological Resources Preservation Act — 16 U.S.C. § 470aaa(accessed 2026-07-01)
Last verified: 2026-07-01 · Last updated: 2026-07-01